Although this is not a דקדוק issue per se, it does pertain to קריאת התורה and would be the most appropriate of my blogs to cover it.
When מטות and מסעי are read together, the עליה which joins the two פרשיות does not end at שני of מסעי but rather, it continues until שלישי. There seems to be good reason for this. מגן אברהם תכ"ח:ח cites צרור המור, stating that one must not make a break in the middle of the מסעות, the פסוקים dealing with the list of בני ישראל's resting points in the מדבר. The reason for this is that there are 42 venues, corresponding to one of the Divine names.
For 21 years leading up to 2005, this was not an issue, at least in חוץ לארץ. It came up in 2005, 2008, 2011 and now 2014 but once again will become dormant for 21 years.
When we read מסעי on its own, where do we end the first עליה? Most חומשים have שני planted smack in the middle of the מסעות. Is this not in direct contradiction with the מגן אברהם? Perhaps this issue arises already the שבת before. What do we do at מנחה and then on Monday and Thursday? Does the כהן read all the way until שלישי? There are definitely times (עקב, for example) when dancing around illegal stopping points causes us to read an abnormally large chunk, and sometimes (ואתחנן for example) even past שני, even on Monday and Thursday.
For 21 years leading up to 2005, this was not an issue, at least in חוץ לארץ. It came up in 2005, 2008, 2011 and now 2014 but once again will become dormant for 21 years.
When we read מסעי on its own, where do we end the first עליה? Most חומשים have שני planted smack in the middle of the מסעות. Is this not in direct contradiction with the מגן אברהם? Perhaps this issue arises already the שבת before. What do we do at מנחה and then on Monday and Thursday? Does the כהן read all the way until שלישי? There are definitely times (עקב, for example) when dancing around illegal stopping points causes us to read an abnormally large chunk, and sometimes (ואתחנן for example) even past שני, even on Monday and Thursday.
With regards to מנחה on שבת and Monday and Thursday, it appears מנהג אשכנז is not to be bothered by this. Even the מגן אברהם would agree that if we are not ultimately reading all 42 of the מסעות, there is no need to ensure they are contiguous. Nevertheless, מנהג ספרד and מנהג חב"ד is to be cautious of this even then. The לוי reads all of the מסעות and the ישראל reads 4 more פסוקים. The מנהג of Munkatcher and Barditchever חסידים is to go one step further and have the כהן read it all, so as not to stop after the very first פסוק of ויסעו מרעמסס. Those who have the כהן stop there would reason that ויסעו בני ישראל מרעמסס is repeated again and thus, the 42 מסעות are still contiguous.
However, the proper procedure on Shabbos is still up for discussion. It is not clear whether the conventional stopping point found in most חומשים should be ignored on account of the צרור המור. This issue should be brought up with your local Rav and as early as possible to give time for necessary investigation. It seems there are two options if one is to adhere to the צרור המור. The entire list of the מסעות can be read by either the כהן or the לוי.
